Real Time Location Systems (RTLSs) track objects, typically by associated tags. They can provide Unique Device Identification (UDI) and may employ Received Signal Strength Indication (RSSI) of RF signals to calculate relative positions. For individuals, a badge is used for tracking in environments such as health-care facilities, warehouses, and other areas where location is important. Personnel badges and asset tags may include RFID, passive or active, to communicate with fixed or hand-held readers.
The Wi-Fi standard (802.11) has been used as the communications protocol for RTLS to interface with the tags and determine their locations. Some tags are intended to, but do not successfully, scale to meet the needs of large enterprises and are limited to small-scale installations. Accuracy in the field can be insufficient to support business needs. For example, accuracy can be hampered by the environment and the location of fixed stations. Some systems are difficult to learn and use, lacking a visual component. Also, the speed of location or identification can be unacceptable. It may take several minutes before some tags transmit and have their location updated. For some, the time interval can be decreased, but a result is unacceptable tag battery life.
These systems monitor people and items with varying levels of accuracy. A need exists for the ability to economically and accurately track assets and their attributes in a scalable system suitable to multiple environments including hospital facilities.